pajamas, or PJs for short, these are the clothes you wear to bed. They are often flannel and really comfy. Some silly girls wear them during the day because they think it's cool. Pajamas are generally fun to wear.

When you sneak up on a sleeping person while they are sleeping on their stomach and have anal sex with them, without waking them up.
Comes from old times, when the butt flap was still popular.
Note! There must be no consent for this to work properly.

John: Dude, you and your woman have a good time last night?
Jack: Yeah, I pajama'd her and she didn't even make a noise!

Nothing. A word made up by the Americans. What they mean is pYjamas. Notice the Y in there. Pyjamas are something you wear to bed. Pajamas don't exist. So there.

American: I'm wearing pajamas to bed. (Means he's going to bed naked)

Brit: I'm wearing pyjamas to bed (means he's going to bed in clothes specifically for sleeping. Probably with Chuck Norris or Superman on the front. Or Scooby Doo. I used to love Scooby Doo back in the day. Its still pretty good but you need to find a decent excuse to watch it - like having a little brother or something.)